Make functions static in unittests

Make functions static in unittests

Enabling -Wmissing-declarations points out that a bunch of function in
the unittests can be made static, do that.

gdb/ChangeLog:

	* unittests/array-view-selftests.c (check_ptr_size_ctor2): Make
	static.
	* unittests/basic_string_view/capacity/1.cc (test01): Likewise.
	* unittests/basic_string_view/cons/char/1.cc (test01): Likewise.
	(main): Likewise.
	* unittests/basic_string_view/cons/char/2.cc (test03): Likewise.
	(main): Likewise.
	* unittests/basic_string_view/cons/char/3.cc (test05): Likewise.
	(main): Likewise.
	* unittests/basic_string_view/element_access/char/1.cc (test01): Likewise.
	(main): Likewise.
	* unittests/basic_string_view/element_access/char/empty.cc (main): Likewise.
	* unittests/basic_string_view/element_access/char/front_back.cc (test01): Likewise.
	(main): Likewise.
	* unittests/basic_string_view/inserters/char/2.cc (test05): Likewise.
	(main): Likewise.
	* unittests/basic_string_view/modifiers/remove_prefix/char/1.cc (test01): Likewise.
	(main): Likewise.
	* unittests/basic_string_view/modifiers/remove_suffix/char/1.cc (test01): Likewise.
	(main): Likewise.
	* unittests/basic_string_view/modifiers/swap/char/1.cc (test01): Likewise.
	* unittests/basic_string_view/operations/compare/char/1.cc (test01): Likewise.
	(main): Likewise.
	* unittests/basic_string_view/operations/compare/char/13650.cc (test01): Likewise.
	* unittests/basic_string_view/operations/copy/char/1.cc (test01): Likewise.
	(main): Likewise.
	* unittests/basic_string_view/operations/data/char/1.cc (test01): Likewise.
	(main): Likewise.
	* unittests/basic_string_view/operations/find/char/1.cc (test01): Likewise.
	(main): Likewise.
	* unittests/basic_string_view/operations/find/char/2.cc (test02): Likewise.
	(main): Likewise.
	* unittests/basic_string_view/operations/find/char/3.cc (test03): Likewise.
	(main): Likewise.
	* unittests/basic_string_view/operations/find/char/4.cc (main): Likewise.
	* unittests/basic_string_view/operations/rfind/char/1.cc (test01): Likewise.
	(main): Likewise.
	* unittests/basic_string_view/operations/rfind/char/2.cc (test02): Likewise.
	(main): Likewise.
	* unittests/basic_string_view/operations/rfind/char/3.cc (test03): Likewise.
	(main): Likewise.
	* unittests/basic_string_view/operations/substr/char/1.cc (test01): Likewise.
	(main): Likewise.
	* unittests/basic_string_view/operators/char/2.cc (main): Likewise.
	* unittests/optional/assignment/1.cc (test): Likewise.
	* unittests/optional/assignment/2.cc (test): Likewise.
	* unittests/optional/assignment/3.cc (test): Likewise.
	* unittests/optional/assignment/4.cc (test): Likewise.
	* unittests/optional/assignment/5.cc (test): Likewise.
	* unittests/optional/assignment/6.cc (test): Likewise.
	* unittests/optional/assignment/7.cc (test): Likewise.
	* unittests/optional/cons/copy.cc (test): Likewise.
	* unittests/optional/cons/default.cc (test): Likewise.
	* unittests/optional/cons/move.cc (test): Likewise.
	* unittests/optional/cons/value.cc (test): Likewise.
	* unittests/optional/in_place.cc (test): Likewise.
	* unittests/optional/observers/1.cc (test): Likewise.
	* unittests/optional/observers/2.cc (test): Likewise.

Change-Id: I66626db864cb877cacc570d4660df633530554f5